The test may be done in your health care provider's office. The joint to be biopsied will be positioned so there is easy access. The joint will be injected with a local anesthetic.

Next, an instrument (trocar) used to force fluid from a cavity is inserted into the joint space. The biopsy needle is inserted through the trocar and twisted to cut out a tissue segment. The biopsy needle is removed and the trocar is removed. The biopsy site is cleansed and pressure and bandage are applied.

This procedure may also be performed in a hospital via arthroscopy.

Inform your health care provider of any drug allergies you have, which medications you are taking (including any herbal medicines and supplements), if you have bleeding problems, and if you are pregnant. You must sign a consent form.

For infants and children:

The preparation you can provide for this test depends on your child's age and experience. For specific information regarding how you can prepare your child, see the following topics:

• Infant test/procedure preparation (birth to 1 year)
• Toddler test/procedure preparation (1 to 3 years)
• Preschooler test/procedure preparation (3 to 6 years)
• Schoolage test/procedure preparation (6 to 12 years)
• Adolescent test/procedure preparation (12 to 18 years)

With the local anesthetic, you will feel a prick and a burning sensation. As the trocar is inserted, there will be some discomfort.

Synovial biopsy helps diagnose gout, bacterial infections, or other infections and may suggest the presence of inflammatory conditions, such as autoimmune disorders.

Synovial biopsy may identify the following conditions:

• Coccidioidomycosis (a fungal infection)
• Fungal arthritis
• Gout (urate crystals that form in the joints)
• Hemochromatosis (abnormal accumulation of iron deposits)
• Tuberculosis
• Synovial cancer

The test may help diagnose rheumatoid arthritis and other autoimmune diseases.

There is a very slight chance of infection and bleeding. Rarely, there is a chance of the needle striking a nerve or blood vessel.